14,228 research outputs found
Metal System for Chemical Reactions and for Studying Properties of Gases and Liquids
An all-metal system, made of copper, is herein described. It is suitable for working with those chemicals which do not attack copper. In particular it has been found very useful in the purification of BF3 and B(CH3)3. Some important features of such a system are (1) a complete absence of contaminants; (2) reactions may be carried out up to 500°C; (3) pressures up to several hundred pounds per square inch may be used; (4) flow of gases from very low to very high pressures may be easily controlled; (5) the system is very rugged. This latter point is particularly desirable where noxious or inflammable gases (such as B(CH3)3) are used. A method is also described whereby gases from sealed-off containers under either high or low pressures may be easily retrieved without introducing impurities. Other important advantages of such a system are mentioned in the text
Performance Characterization Using AoI in a Single-loop Networked Control System
The joint design of control and communication scheduling in a Networked
Control System (NCS) is known to be a hard problem. Several research works have
successfully designed optimal sampling and/or control strategies under
simplified communication models, where transmission delays/times are negligible
or fixed. However, considering sophisticated communication models, with random
transmission times, result in highly coupled and difficult-to-solve optimal
design problems due to the parameter inter-dependencies between
estimation/control and communication layers. To tackle this problem, in this
work, we investigate the applicability of Age-of-Information (AoI) for solving
control/estimation problems in an NCS under i.i.d. transmission times. Our
motivation for this investigation stems from the following facts: 1) recent
results indicate that AoI can be tackled under relatively sophisticated
communication models, and 2) a lower AoI in an NCS may result in a lower
estimation/control cost. We study a joint optimization of sampling and
scheduling for a single-loop stochastic LTI networked system with the objective
of minimizing the time-average squared norm of the estimation error. We first
show that under mild assumptions on information structure the optimal control
policy can be designed independently from the sampling and scheduling policies.
We then derive a key result that minimizing the estimation error is equivalent
to minimizing a function of AoI when the sampling decisions are independent of
the state of the LTI system. Noting that minimizing the function of AoI is a
stochastic combinatorial optimization problem and is hard to solve, we resort
to heuristic algorithms obtained by extending existing algorithms in the AoI
literature. We also identify a class of LTI system dynamics for which
minimizing the estimation error is equivalent to minimizing the expected AoI.Comment: 7 pages, IEEE Infocom AoI Workshop, 201
Multi-aspect, robust, and memory exclusive guest os fingerprinting
Precise fingerprinting of an operating system (OS) is critical to many security and forensics applications in the cloud, such as virtual machine (VM) introspection, penetration testing, guest OS administration, kernel dump analysis, and memory forensics. The existing OS fingerprinting techniques primarily inspect network packets or CPU states, and they all fall short in precision and usability. As the physical memory of a VM always exists in all these applications, in this article, we present OS-Sommelier+, a multi-aspect, memory exclusive approach for precise and robust guest OS fingerprinting in the cloud. It works as follows: given a physical memory dump of a guest OS, OS-Sommelier+ first uses a code hash based approach from kernel code aspect to determine the guest OS version. If code hash approach fails, OS-Sommelier+ then uses a kernel data signature based approach from kernel data aspect to determine the version. We have implemented a prototype system, and tested it with a number of Linux kernels. Our evaluation results show that the code hash approach is faster but can only fingerprint the known kernels, and data signature approach complements the code signature approach and can fingerprint even unknown kernels
Economic Analysis of Transaction Cost on Kolaramma Tank Watershed in Eastern Dry Zone of Karnataka
The transaction cost incurred on the Kolaramma tank watershed in the Kolar district of Karnataka, with a geographical area of 6,570 hectares and covering 26 catchments has been found to be Rs 78,89,210. The decomposition of this transaction cost into information, contractual and enforcement costs has revealed that enforcement cost amounted to a vast share of 82.0 per cent, followed by contractual cost (13.6%) and information cost (4.4%) in the total transaction cost. Considering the overall transaction cost, the investment on information and contractual cost has been quite less. These need to be increased by economizing on the administrative expenses of the implementing agency. Any additional investment on information and contractual cost would greatly benefit the actual beneficiaries in the watershed.Resource /Energy Economics and Policy,
Self-organization via active exploration in robotic applications
We describe a neural network based robotic system. Unlike traditional robotic systems, our approach focussed on non-stationary problems. We indicate that self-organization capability is necessary for any system to operate successfully in a non-stationary environment. We suggest that self-organization should be based on an active exploration process. We investigated neural architectures having novelty sensitivity, selective attention, reinforcement learning, habit formation, flexible criteria categorization properties and analyzed the resulting behavior (consisting of an intelligent initiation of exploration) by computer simulations. While various computer vision researchers acknowledged recently the importance of active processes (Swain and Stricker, 1991), the proposed approaches within the new framework still suffer from a lack of self-organization (Aloimonos and Bandyopadhyay, 1987; Bajcsy, 1988). A self-organizing, neural network based robot (MAVIN) has been recently proposed (Baloch and Waxman, 1991). This robot has the capability of position, size rotation invariant pattern categorization, recognition and pavlovian conditioning. Our robot does not have initially invariant processing properties. The reason for this is the emphasis we put on active exploration. We maintain the point of view that such invariant properties emerge from an internalization of exploratory sensory-motor activity. Rather than coding the equilibria of such mental capabilities, we are seeking to capture its dynamics to understand on the one hand how the emergence of such invariances is possible and on the other hand the dynamics that lead to these invariances. The second point is crucial for an adaptive robot to acquire new invariances in non-stationary environments, as demonstrated by the inverting glass experiments of Helmholtz. We will introduce Pavlovian conditioning circuits in our future work for the precise objective of achieving the generation, coordination, and internalization of sequence of actions
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